1、Designation: E1938 08E1938 13Standard Test Method forDetermination of Titanium in Nickel Alloys byDiantipyrylmethane Molecular AbsorptionSpectrometrySpectrophotometry1This standard is issued under the fixed designation E1938; the number immediately following the designation indicates the year oforig
2、inal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of titanium in nickel
3、 alloys in the range 0.3 % to 5.0 %. With appropriatereference materials, the test method may be extended down to 0.05 %.1.2 Molybdenum, if present, may cause a high bias to the extent of 0.001 % titanium for every 1 % molybdenum.1.3 The values stated in SI units are to be regarded as standard. No o
4、ther units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability
5、 of regulatorylimitations prior to use. For specific hazards associated with the use of this test method, see Practices E50.2. Referenced Documents2.1 ASTM Standards:2E50 Practices forApparatus, Reagents, and Safety Considerations for ChemicalAnalysis of Metals, Ores, and Related MaterialsE135 Termi
6、nology Relating to Analytical Chemistry for Metals, Ores, and Related MaterialsE882 Guide for Accountability and Quality Control in the Chemical Analysis LaboratoryE1601 Practice for Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical Method2.2 ISO Standards:3ISO 5725:19
7、86 Precision of Test MethodsDetermination of Repeatability and Reproducibility for a Standard Test Method byInter-Laboratory TestsISO 11433:1993(E) Nickel AlloysDetermination of Titanium ContentDiantipyrylmethane Molecular Absorption Spectro-metric Method3. Terminology3.1 DefinitionsFor definitions
8、of terms used in this test method, refer to Terminology E135.4. Summary of Test Method4.1 This test sample is dissolved in a mixture of HCl and HNO3. The solution is evaporated to fumes of H2SO4 to remove theHCl and HNO3. Color is developed with diantipyrylmethane, and the absorbance is measured at
9、390 nm.5. Significance and Use5.1 This test method is used for the determination of titanium in nickel alloy samples by molecular absorption spectrometry tocheck compliance with compositional specifications. It is assumed that all who use the procedure will be trained analysts capableof performing c
10、ommon laboratory procedures skillfully and safely. It is expected that the work will be performed in a properlyequipped laboratory and that proper waste disposal procedures will be followed. Appropriate quality control practices must befollowed such as those described in Guide E882.1 This test metho
11、d is under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for Metals, Ores, and Related Materials and is the direct responsibility ofSubcommittee E01.08 on Ni and Co and High Temperature Alloys.Current edition approved Dec. 15, 2008Oct. 1, 2013. Published January 2009November 2013. O
12、riginally approved in 1997. Last previous edition approved in 20022008as E1938 02.E1938 08. DOI: 10.1520/E1938-08.10.1520/E1938-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume informat
13、ion, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an
14、 indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to
15、 be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Apparatus6.1 Spectrophotometer, capable of measuring absorbance at a wavelength of 390 nm.6.2 Cells, to fit spectrophotometer, having an optical p
16、ath of 1 cm.NOTE 1Cells having other dimensions can be used, provided suitable adjustments can be made in the amount of sample and reagents used.7. Reagents7.1 Purity and Concentration of ReagentsThe purity and concentration of common chemical reagents and water shall conformto Practices E50. The re
17、agents should be free of or contain only minimal amounts ( 0.1 g/g) of titanium.7.2 Potassium Hydrogen Sulfate (KHSO4).7.3 Ascorbic Acid SolutionDissolve 20 g of ascorbic acid (C6H8O6) in water, dilute to 200 mL, and mix.7.4 Oxalic Acid SolutionDissolve 10 g of oxalic acid dihydrate (COOH)22H2O in w
18、ater, dilute to 200 mL, and mix.7.5 Diantipyrylmethane SolutionDissolve 4 g of diantipyrylmethane monohydrate (C23H24N4O2H2O) in water containing25 mL HCl (1 + 1). Dilute to 200 mL and mix.7.6 Sodium Chloride SolutionDissolve 117 g of sodium chloride (NaCl) in water, dilute to 500 mL, and mix.7.7 Ti
19、tanium Stock Calibration Solution (200 g/mL Ti)Dissolve 0.739 g of potassium titanyl oxalate dihydrateK2TiO(C2O4)22H2O in water. Add 50 mL of H2SO4 (1 + 1) and evaporate to dense fumes. Cool, dilute, and transfer the roomtemperature solution to a 500-mL volumetric flask. Dilute to the mark and mix.7
20、.7.1 Alternative Preparation:Transfer 0.1000 g of titanium metal (purity: 99.9 % minimum) weighed to within 6 0.2 mg to a500-mL glass volumetric flask. Add 50 mL of H2SO4 (1 + 3) and dissolve over low heat. Oxidize the titanium by adding HNO3dropwise until the blue color is just discharged (avoid ex
21、cess HNO3 which will cause the titanium to precipitate). Cool to roomtemperature and dilute to volume with H2SO4 (1 + 9).7.8 Titanium Calibration Solution (25 g/mL Ti)Transfer 25.0 mL of the titanium stock calibration solution to a 200-mLvolumetric flask. Add 20 mL of H2SO4 (1 + 1). Cool the solutio
22、n to room temperature, dilute to the mark, and mix.8. Sampling and Sample Preparation8.1 Sampling shall be done by normal procedures agreed upon between the parties, or in the event of a dispute, according tothe relevant standard, if one is available.8.2 The laboratory sample is normally in the form
23、 of millings or drillings and no further preparation of the sample is necessary.8.3 If it is suspected that the laboratory sample is contaminated with oil or grease from the milling or drilling operation, it shallbe cleaned by washing it with high purity acetone, or other appropriate solvent, and dr
24、ying in air.8.4 If the sample contains particles or pieces of widely varying sizes, the test sample should be obtained by riffling.9. Procedure9.1 Preparation of Test Solution:9.1.1 Test PortionWeigh the test portion of the sample in accordance with Table 1.9.1.2 Dissolution of Test PortionTransfer
25、the test portion to a 125-mL Erlenmeyer flask and add 10 mL of HC1 and 3 mL ofHNO3.Apply sufficient heat to initiate and maintain the reaction until dissolution is complete. If the alloy resists dissolution, someadjustment in the acid mixture may be required. Add HC1 in 1-mL increments and continue
26、heating to dissolve the test portion.9.1.3 Preparation of Final Test Solution:9.1.3.1 Add 7 mL of H2SO4 (1 + 1) and evaporate the solution until dense white fumes appear. Cool the contents and proceedas directed in 9.1.3.2 or 9.1.3.3, depending on whether tantalum is present in the sample or not.9.1
27、.3.2 In the absence of tantalum, add 20 mL of oxalic acid solution and heat to dissolve the salts. Cool the solution and, intungsten free alloys, proceed as directed in 9.1.4. If the alloy contains tungsten, add sufficient ammonium hydroxide to make thesolution alkaline. Boil the solution until the
28、tungstic acid is dissolved. Cool the solution and re-acidify by adding 20 mL of HC1.Cool the solution and proceed as directed in 9.1.4.9.1.3.3 In the presence of tantalum, add 30 mL of water, heat to dissolve the salts and cool again. Filter the solution througha tightly packed filter pulp pad. Wash
29、 the precipitate with warm water. Retain the filtrate. Transfer the pad and precipitate to aplatinum crucible, ignite at 800 C, and cool. Add 1 g of potassium pyrosulfate, cover the crucible with a platinum lid and fuseTABLE 1 Weight of Sample to be TakenExpected Ti Content,%Weight of Test Portion,g
30、0.3 to 3.0 0.19 to 0.213.0 to 5.0 0.09 to 0.11E1938 132carefully over a flame. Cool and transfer the crucible to a 150-mL beaker containing 20 mL of the oxalic acid solution. Heatcarefully until the melt is dissolved. Wash and remove the platinum crucible. Combine the oxalate solution with the origi
31、nal filtrateand proceed as directed in 9.1.4.9.1.4 Dilutions:9.1.4.1 Dilution for Less Than 1 % TitaniumTransfer the test solution (see 9.1.3.2 or 9.1.3.3) to a 100-mL volumetric flask,dilute to the mark, and mix.9.1.4.2 Dilution for 1 % to 5 % TitaniumTransfer the test solution (see 9.1.3.2 or 9.1.
32、3.3) to a 250-mL volumetric flask, diluteto the mark, and mix.9.2 Color Development:9.2.1 With a pipet, transfer 5.0-mL aliquots of the test solution to each of two 50-mL volumetric flasks.9.2.2 Add 5.0 mLof HC1 (1 + 1), 5.0 mLof ascorbic acid solution and 20.0 mLof NaCl solution to both volumetric
33、flasks. Mixthe solutions and allow to stand for a few minutes.9.2.3 Add 10.0 mL of diantipyrylmethane solution to one of the volumetric flasks.9.2.4 Dilute both flasks to the mark, mix, and allow to stand for 40 min.9.3 Spectrophotometric Measurement:9.3.1 Using a 1-cm cell, measure the absorbance o
34、f both solutions against water as the reference at a wavelength of 390 nm withthe spectrophotometer.9.3.2 Subtract the background absorbance of the test solution from the absorbance of the test solution containing thediantipyrylmethane complex.9.4 Blank TestPerform a blank test in parallel with the
35、determination following the same procedure and using the samequantities of reagents.9.5 Calibration:9.5.1 Using a microburette, transfer (0, 1.0, 2.0, 3.0, 4.0 and 5.0) mL of the titanium calibration solution to a series of 50-mLvolumetric flasks.9.5.2 Add HC1 (1 + 1), ascorbic acid and NaCl solutio
36、n to each of the volumetric flasks. Mix the solutions and allow to standfor a few minutes.9.5.3 Add 10.0 mL of diantipyrylemethane solution to each of the solutions, dilute to the marks, and mix. Allow to stand for40 min. This series corresponds to (0, 0.5, 1.0, 1.5, 2, and 2.5) g titanium per milli
37、litre.9.5.4 Measure the absorbance of the calibration solutions as described in 9.3. Subtract the measured absorbance of the 0 g/mLcalibration solution from the absorbance values of the remaining calibration solutions.9.5.5 Plot the corrected absorbance values against the respective concentrations o
38、f titanium, in micrograms per millilitre, in thecalibration solutions.9.6 Number of DeterminationsPerform the determinations at least in duplicate.9.7 Check Test, The performance of the test method may be checked by analyzing, in parallel with the determinations andfollowing the same procedure, one
39、or more samples of the same type alloy whose titanium content is known.10. Calculation10.1 Determine the concentration of the titanium in the test solutions and the blank by means of the calibration graph.10.2 Calculate the titanium content CTi, expressed as a percentage by weight of the test portio
40、n using the formula:CTi 5A 2B!C1024!/5D (1)where:A = the titanium concentration in g/mL of the test solution,B = the titanium concentration in g/mL of the blank test solution,C = the final dilution volume in mL of the test solution, andD = the sample weight in g.TABLE 2 Nominal Composition of Test S
41、amples (in %)TestMaterialAl Co Cr Fe Hf Mo Nb Ta Ti W NiRE-2 0.5 0.5 20 18 3 5 1.0 BalanceRE-1 5.5 10 9 1.6 2.6 1.5 10 BalanceRE-3 1.9 19 22 1 1.4 3.7 2 BalanceRE-4 3.0 10 14 4 5.0 4 BalanceE1938 13311. Precision and Bias411.1 PrecisionEleven laboratories in four countries participated in testing th
42、is method under the auspices of ISO/TC155/SC4in the late 1980s and published as ISO 11433:1993(E). Four samples of nominal composition given in Table 2 were tested to obtainthe statistical information, as evaluated by ISO 5725:1986 and equivalent to Practice E1601, summarized in Table 3. Precision m
43、aybe judged by examination of these data.11.2 BiasNo information on the accuracy of this test method is known because accepted reference standards were not usedin the interlaboratory study. The user of this test method is encouraged to use accepted reference materials, if available, todetermine the
44、accuracy of this test method as it applies in a specific laboratory.12. Keywords12.1 molecular absorption spectrometry; nickel alloy; spectrophotometric; titanium contentASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin
45、 this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and mus
46、t be reviewed every five years andif not revised, either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of ther
47、esponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700,
48、 West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission
49、rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).4 Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:E01-1025.TABLE 3 Results of Statistical AnalysisTitaniumTestMaterialAMean%Repeatability Index,r (Practice E1601)Reproducibility Index,R (Practice E1601)RE-2 0.37 0.019 0.038RE-1 1.49 0.041 0.084RE-3 3.69 0.050 0.088RE-4 5.09 0.063 0.139A Material compositions are summarized in Table 2.E1938 134
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